Ambisonics provides a full-sphere surround sound technique. In addition to providing surround sound in the horizontal plane, ambisonics also covers sound sources above and below the listener. Unlike other multichannel surround formats, ambisonics transmission channels do not carry speaker signals but instead contain a speaker-independent representation of a sound field called B-format, which is then decoded to the listener's speaker setup. This extra step allows the producer to design audio in terms of source directions rather than in terms of loudspeaker positions, and offers the listener a considerable degree of flexibility as to the layout and number of speakers used for playback.
In ambisonics, an array of virtual loudspeakers surrounding a listener can generate a sound field by decoding a B-format sound file generated from a sound source that is isotropically recorded. In an example implementation, such decoding can be used in the delivery of audio through headphone speakers in Virtual Reality (VR) systems. Binaurally rendered high-order ambisonics (HOA) refers to the creation of many (e.g., at least 16) virtual loudspeakers that combine to provide a pair of signals to left- and right-channel speakers.